generator 实现 for of

[wenJonSnow]

function* objectEntries(obj) {
let propKeys = Reflect.ownKeys(obj);

for (let propKey of propKeys) {
  yield [propKey, obj[propKey]];
}
}

let jane = { first: 'Jane', last: 'Doe' };

for (let [key, value] of objectEntries(jane)) {
console.log(`${key}: ${value}`);
}
// first: Jane
// last: Doe

function* objectEntries() {
  let propKeys = Object.keys(this);

  for (let propKey of propKeys) {
    yield [propKey, this[propKey]];
  }
}

let jane = { first: 'Jane', last: 'Doe' };

jane[Symbol.iterator] = objectEntries;

for (let [key, value] of jane) {
  console.log(`${key}: ${value}`);
}
// first: Jane
// last: Doe